How Global Variables are getting processed at the background ??

Hi all,
Im new to BODS. My team is doing a research and i wanted to know how the global variables,which we are declaring in BODS, are getting processed at the background ?

Suppose we give 'Y' as global variable and when it starts getting executed, it will be converted to something else like maybe hexadecimal,etc.

I want to know how this conversion happens and what it is getting converted to.

Thanks in advance.